A recent study published in Soil Biology and Biochemistry highlights the significant role of maize straw mulching and no-till practices in improving nitrogen fertilizer efficiency and long-term nitrogen retention in the black soil region of Northeast China.

Researchers from the Institute of Applied Ecology, Chinese Academy of Sciences, led by Dr. HE Hongbo, investigated the time-dependent distribution of ¹⁵N-labeled fertilizer nitrogen among soil aggregates of different sizes. The study aimed to understand the mechanisms underlying the stabilization of residual fertilizer nitrogen in soil microstructures under straw mulching.

Results indicate that smaller aggregates, particularly the silt-clay fraction (<53 µm), experience rapid losses of fertilizer-derived nitrogen in the early stages of the experiment. In contrast, larger macroaggregates (250-2000 µm) serve as long-term nitrogen reservoirs, balancing nitrogen stabilization and turnover. This dynamic process, characterized by a continuous cycle of releasing old and assimilating new nitrogen, is further enhanced by straw mulching. By increasing the retention of fertilizer nitrogen in particulate organic matter (POM) within macroaggregates and reducing losses in mineral-associated organic matter (MAOM), straw mulching improves the long-term stability of fertilizer nitrogen in soil.

These findings provide valuable insights into sustainable agricultural practices for enhancing soil health and reducing nitrogen losses in the black soil region.